A rendering of what the tower would look like within the Transbay Transit Center and on the San Francisco skyline.

A 1,070-foot tower that will become the largest skyscraper on the West Coast received its final approvals from the Planning Commission on Thursday.

It marks a significant step forward for the project, which is a key piece of the Transit Center District Plan that will redevelop the area around the new Transbay Transit Center in South of Market. The new hub, which is being rebuilt at First and Mission streets, will eventually be the downtown terminus for Caltrain and the future state high-speed rail network.

“I think the vote came out great because it allows the project to move forward,” said Paul Paradis, senior managing director at project developer Hines.

Before the Planning Commission voted on the final approvals, Fred Clarke of Pelli Clarke Pelli, the architect for Hines, unveiled the latest small changes to the plans, including a new elevator that will tie the tower together with City Park, a quarter-mile stretch of open space atop the transit center. The building and the open space also will be connected by a 30-foot-wide pedestrian bridge that will extend from the fifth floor of the tower, which will house retail space, according to the architects.

Clarke also showed the Planning Commission the actual metal and glass that will be used on the exterior of the building. He explained that the skin of the building has been augmented to add metalwork that will grow deeper and denser at the bottom of the tower. Clarke said adding the metal to the glass exterior will give the building a light texture that will glow in an ambient way.

The metalwork also was used to make the building safer for birds and to help control the flow of water down the structure.

Some people speaking about the project decried the tower as being too large and criticized its design.

Commissioner Gwyneth Borden noted that the plans and design for the Transamerica Pyramid were widely panned at the time, but that the building has become an icon.

Others lauded the design, which has the tower gently tapering in as it rises.

“I think this is going to be San Francisco’s greatest tower,” Planning Commission President Rodney Fong said.

Several commissioners also made a request for the developers to include an observation deck that would be open to the public.

“I think the request to investigate the observation deck is reasonable and we will certainly work with staff to fully investigate that topic,” Paradis said after the meeting.

The next step is Hines buying the land, which is currently owned by the Transbay Joint Powers Authority.